Guiding structure for transforming a gaussian type propagation mode profile into a widened type propagation mode profile and application to the manufacture of a wavelength multiplexer / demultiplexer

Abstract

The invention proposes a guiding structure capable of transforming a lightwave with at least one central wavelength λ i with a Gaussian type propagation mode profile coming out of the introduction means into a widened type propagation mode profile, this structure comprising: a first guiding part ( 1 ), and a second part ( 2 ) comprising at least one microguide ( 3 ), with one end ( 5 ) in the form of a Y, the first and second part and the introduction means are connected to each other such that when the lightwave is introduced into either the first or the second part, it is transformed into the other part into a widened profile for the central wavelength λ i . The invention is applicable to the manufacture of a large number of optical components, and particularly wavelength multiplexers and demultiplexers.

1 . Guiding structure capable of transforming a lightwave with at least one central wavelength λ i  with a Gaussian type propagation mode profile coming out of the introduction means (S, S′) into a widened type propagation mode profile, this structure comprising: 
 a first guiding part ( 1 ), and  
 a second part ( 2 ) comprising at least one microguide, with one end ( 5 ) in the form of a Y, the first and second part and the introduction means are optically connected to each other such that when the lightwave is introduced into either the first or the second part, it is transformed into the other part into a widened profile for the central wavelength λ i .  
 
     
     
         2 . Guiding structure according to  claim 1 , characterized in that the means (S) of introducing the lightwave are provided at at least one of the ends of the first part, the other end of the said first part being optically connected to the Y end of the second part, the said widened profile then being obtained in the second part.  
     
     
         3 . Guiding structure according to  claim 1 , characterized in that the means (S′) of introducing the lightwave are placed at at least one of the ends of the second part, the other end corresponding to the Y shaped end is optically connected to one of the ends of the first part, the said widened profile then being obtained in the first part.  
     
     
         4 . Guiding structure according to  claim 2 , characterized in that the first part consists of free space.  
     
     
         5 . Guiding structure according to  claim 2 , characterized in that the first part comprises a planar guide.  
     
     
         6 . Guiding structure according to either of claims  2  or  3 , characterized in that the first part comprises at least one optical fibre, with at least one of its ends being optically connected to the Y shaped end of a microguide in the second part.  
     
     
         7 . Guiding structure according to either of claims  2  or  3 , characterized in that the first part comprises at least one optical microguide, with at least one of its ends being optically connected to the Y shaped end of a microguide in the second part.  
     
     
         8 . Guiding structure according to  claim 7 , characterized in that the end of the microguide optically connected to the second part is in the form of a Y.  
     
     
         9 . Guiding structure according to any one of claims  1  or  8 , characterized in that the Y shaped end comprises two distinct guiding parts that join together into a single guiding part.  
     
     
         10 . Guiding structure according to any one of claims  1  or  8 , characterized in that the Y shaped end forms a taper.  
     
     
         11 . Guiding structure according to  claim 1 , characterized in that the means of introducing the lightwave comprise at least one light source optically connected to one of the parts.  
     
     
         12 . Guiding structure according to  claim 1 , characterized in that the first part and the second part are optically connected to each other through reflection means.  
     
     
         13 . Guiding structure according to  claim 12 , characterized in that the reflection means are chosen to be a diffraction grating or a holographic grating.  
     
     
         14 . Guiding structure according to any one of claims  1  or  13  used to make a demultiplexer, characterized in that the means of introduction emit a lightwave in one of the parts at several different central wavelengths λ 1 , λ 2 , . . . λ i , . . . λ n  and that the other part comprises at least n microguides G i  where i is between 1 and n; each microguide G i  being capable of guiding a central wavelength λ i , the first and the second parts being optically connected such that only a single central wavelength λ i  is focused at the input to each microguide G i .  
     
     
         15 . Guiding structure according to  claim 14 , characterized in that the first and second parts are connected together through reflection means reflecting each central wavelength λ i  at a particular angle, so that a single central wavelength λ i  can be focussed at the input to a single microguide G i .  
     
     
         16 . Guiding structure according to any one of  claims 1  to  13  used to make a multiplexer, characterized in that the introduction means emit a lightwave into one of the parts formed from several lightwaves with different central wavelengths λ i , and in that the other part comprises a microguide capable of guiding all central wavelengths λ i , the first and the second parts being optically connected such that the different central wavelengths λ i  are focused at the input to the microguide of the said other part.